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Precise LED lamps dimming for stage technology
Šojdr, Marek ; Šteffan, Pavel (referee) ; Levek, Vladimír (advisor)
This bachelor´s thesis discusses the problems of dimming of LED bulbs using DC voltage. It explains basic converters topologies and power factor correction options. Part of the thesis deals with the subharmonic oscillation and possibilities of its elimination. Describes the design of the circuitry of dimmer module for precise dimming of selected types of LED bulbs, revival and testing of the dimmer module. Part of the work is basic for realization of the dimmer (printed circuit board, list of components).
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DC-DC converter for onboard charging of electric vehicles
Holub, Miroslav ; Červinka, Dalibor (referee) ; Folprecht, Martin (advisor)
This master thesis deals with design of DC-DC converter for onboard charging of electric vehicle. Developed converter will mainly be used for charging stationary traction battery in laboratory. Output voltage of this charger will be adjustable by user in between 200 V and 450 V depending on the current charged battery configuration. Output current limit is set at 8 A. Since the converter will be supplied from standard household socket, the problem of power factor correction must be solved during the design. That is because a large part of this thesis is focused on describing the problematics of power factor correction. After that, active PFC module is designed, completed and performance of this module is verified. To achieve low overall losses and thus be able to keep small volume of the system, modern switching components based on Silicon Carbide were preferred. Beside laboratory use, completed system will be used to emphasize volumetric difference between onboard chargers based on old versus modern switching components.
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The system of load matching to the energy converter
Halama, Petr ; Mandlík, Michal (referee) ; Drexler, Petr (advisor)
This master’s thesis deals with energy harvesting from the mechanical energy sources. The mechanical energy may be converted into the electrical by means of a vibrational microgenerator. The thesis deals also with the production of energy from different renewable sources. There have been identified conditions for effective transformation of the remaining energy. In order to satisfy these conditions a circuit for load matching to energy harvester has to be used. Four variants of matching circuit have been designed and analyzed in PSpice or LTspice. It has been designed a system of power factor correction controlled by circuit with discrete components and also by microcontroller. For one of these variants a specific integrated circuit has been used. The designed circuits have been built and their parameters haven been determined by measurement.
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Functional model of a small hydro power plant control unit
Rusnák, František ; Arm, Jakub (referee) ; Benešl, Tomáš (advisor)
This semester work deals with realization of functional model of control unit for hydroelectric power station. Main task of this work is realization rectifier with active power factor correction, which is used instead of commonly used frequency converter. Control unit is designed for asynchronous motor in generator operation with self-excitation. The propeller turbine is used as propulsion. Theoretical part includes theory of the PFC converters. Practical part includes calculations for components of PFC converter and assembly of DPS PFC converter.
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Ultra low noise switching power supply
Raba, Jaroslav ; Leuchter,, Jan (referee) ; Šrámek, Petr (advisor)
This thesis deals with the issue of switching power supply in terms of noise ratios in the output voltage. In the theoretical part analyzes the basic principle of classical and resonant topology switching power converters in terms of output voltage ripple and switching noise. There are also some possibilities of compensation to minimize switching noise and output ripple. The second part describes the custom design a low noise switching power supply, which is composed of an active power factor corrector, power converters and ripple limiter. The main power converter is designed as an LLC resonant converter. The last part deals with the actual construction of the proposed source, its measurement and presentation of the results.
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Power Factor Controllers for Switch-Mode Power Supllies
Gálus, Matej ; Steinbauer, Miloslav (referee) ; Murina, Milan (advisor)
The aim of this thesis is to design an active power factor correction (PFC) circuit for correcting a power factor of a switching power supplies. Various possible causes of bad AC mains power factor are discussed. Differences between linear and non-linear loads’ behaviour to AC mains are recognized and discussed. Various passive and active solutions for correcting current displacement and harmonic distortion are reviewed. Boost converter with quasi-resonant switching controlled by Texas Instruments’ UC3855 is chosen for highest total power factor for given power level against other topologies and its high efficiency and lower EMI against traditional boost converter. Various circuit parameters are simulated using PSpice. Complete circuit diagram for an 1kW output power level and worldwide mains voltage compatiblity is designed. After the device prototype was constructed, efficiency measurements were made and measured values are less than expected. This was apparently caused mainly due to absence of saturable reactor and implementation of resistive damping of the quasiresonant circuit’s parasitic resonance. Measured values of power factor are, however, very high and do meet the design expectations.
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Functional model of a small hydro power plant control unit
Rusnák, František ; Arm, Jakub (referee) ; Benešl, Tomáš (advisor)
This semester work deals with realization of functional model of control unit for hydroelectric power station. Main task of this work is realization rectifier with active power factor correction, which is used instead of commonly used frequency converter. Control unit is designed for asynchronous motor in generator operation with self-excitation. The propeller turbine is used as propulsion. Theoretical part includes theory of the PFC converters. Practical part includes calculations for components of PFC converter and assembly of DPS PFC converter.
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DC-DC converter for onboard charging of electric vehicles
Holub, Miroslav ; Červinka, Dalibor (referee) ; Folprecht, Martin (advisor)
This master thesis deals with design of DC-DC converter for onboard charging of electric vehicle. Developed converter will mainly be used for charging stationary traction battery in laboratory. Output voltage of this charger will be adjustable by user in between 200 V and 450 V depending on the current charged battery configuration. Output current limit is set at 8 A. Since the converter will be supplied from standard household socket, the problem of power factor correction must be solved during the design. That is because a large part of this thesis is focused on describing the problematics of power factor correction. After that, active PFC module is designed, completed and performance of this module is verified. To achieve low overall losses and thus be able to keep small volume of the system, modern switching components based on Silicon Carbide were preferred. Beside laboratory use, completed system will be used to emphasize volumetric difference between onboard chargers based on old versus modern switching components.
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Precise LED lamps dimming for stage technology
Šojdr, Marek ; Šteffan, Pavel (referee) ; Levek, Vladimír (advisor)
This bachelor´s thesis discusses the problems of dimming of LED bulbs using DC voltage. It explains basic converters topologies and power factor correction options. Part of the thesis deals with the subharmonic oscillation and possibilities of its elimination. Describes the design of the circuitry of dimmer module for precise dimming of selected types of LED bulbs, revival and testing of the dimmer module. Part of the work is basic for realization of the dimmer (printed circuit board, list of components).
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